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Connecting an external display on a 15" MacBook Pro always forces discrete graphics when available. And if you force using the internal GPU with gfxcardstatus, the external display remains blank. Reply

Sadly, the author mix Ultra HD and 4K, Apple specifications clearly states different frequencies for both resolutions, seems the article is not clear with what a MBPr 13" supports at which frequency: "The 13-inch Haswell rMBP unfortunately doesn't support 4K60, although you can use its HDMI port to drive a 4K panel at 30Hz "There are no 4K panel tested here, and Apple states that 4K panels are supported at 24Hz and Ultra HD (the tested displays ehere) at 30Hz "Support for 3840-by-2160 resolution at 30HzSupport for 4096-by-2160 resolution at 24Hz" on this link: http://support.apple.com/kb/SP691

Clearly this is an interesting topic for me and I am deceived by the coverage and the quality of the information given by this article. I hope they will make it clear what is supported for actual Ultra HD (3840x2160) displays, on MBPr 13" Haswell, on which output and which frequency.

I know Nvidea definitely works. I am not sure whether the low end 15 inch Macbook Pro using Iris Pro works with 4K@60Hz or not. Given 13 inch Macbook Pro running similar Intel Iris (not Pro) can't support 4K@60Hz, I think 15 inch Macbook pro using Iris Pro will have similar problem.Reply

On a late 2013 13" MBP/Retina, using SwitchResX, I was able to get the ASUS PB287Q to drive 4K (1920x1060 pixel-doubled "HiDPI") at 45Hz, rather than the max 30Hz offered through the standard Display Prefs pane.

Here's how: I created a custom resolution by copying the 1920x1060 HiDPI 30Hz, and then set its vertical sync to 45Hz (and rebooted as required by SwitchResX). The 45Hz refresh rate is now available in the Display Prefs control panel, and the ASUS OSD confirms we are operating at 45Hz.

Before getting 45 to work, I also tried 50 - but even after reboot it was marked as "invalid" so I suppose I'm maxed out.

The MacBook Pro (Retina, 15-inch, Late 2013) uses H series processors which support up to 3 displays at 3840 x 2160 @ 60 Hz, whereas the 13-inch, Late 2013 models use U series processors which only support 3 displays at up to 3200 x 2000, 24 bpp, 60 Hz, SST. When you use MST to drive a 3840 x 2160 display as two tiles, each tile ends up being 1920 x 2160. I've believe that under Windows 8.1 you can coerce the 13-inch, Late 2013 MacBook Pros to drive a 4K display at 60 Hz by configuring it as two 2160 x 1920 displays in portrait orientation and combining them using Intel's Collage Display Mode. This apparently blanks the built-in display though.Reply

Unfortunately, after installing the 10.9.3 update, I can now drive only one external monitor instead of two, under 10.9.2. I can either drive the 4K monitor or the 2560x1600 one, but not both any more. (Using a late 2013 MacBook Pro, with the 2GB video card.)Reply

When you drive a 4K display at 60 Hz, it uses two display output streams, one for each tile. In essence you are already driving two displays when you run a 4K display at 60 Hz, and you can only drive a maximum of 2 displays via mini DisplayPort / Thunderbolt. However, it is likely you could still drive a 2560x1600 display via the HDMI port in addition to a miniDP connected 4K display.Reply

Except that Haswell only has 3 display controllers. Which means 2 are tied up for the 4K monitor, the 3rd for the built in display. The only way to drive 3 monitors off of a MBP like that would be to have the 4K monitor run at 30Hz (SST instead of MST).Reply

Except the HDMI port of tphinney's MacBook is connected to a NVIDIA GeForce GT 750M which supports 4 display output streams / CRTCs. If you have a discrete GPU, you can drive a 4th display using the HDMI port on the Late 2013 MacBook Pros despite it not being an Apple supported configuration.Reply

I have exactly the same results, under 10.9.3 I can now only drive one external monitor instead of two external. With 10.9.2, I could drive three displays simultaneously: the builtin 15" Retina, an external Thunderbolt Display and an external Dell UP2414Q. All at any combination of resolutions, including the highest res for each. And, while I could only get the Dell to run at 30Hz, I also had the ability to rotate it, very important for me to use it in portrait mode for Aperture work. Sadly, rotation is ALSO missing in action now for the Dell 4K. But I do have 60Hz...one step forward, three steps backward.Reply

I'm sorry if I've overlooked this, but is there any resolution to your problem yet?

I'm on 10.9.5 with a Late 2013 Retina 15" MBP with the NVIDIA GeForce GT 750M, and just upgraded to a NEC PA322UHD external 4K display. When the display is connected via Thunderbolt, I'm able to confirm it's running 3840x2160 @ 60Hz. However, I'm unable to get any secondary external display running on the other Thunderbolt port. Prior to the 4K display, I was able to drive 2 external 2560x1600 displays, one per Thunderbolt port. From reading this thread, it seems the hardware should support one 4K display and one non-4K display, each connected via Thunderbolt. Has there been any solution found? I'm also not able to get a stable output via the HDMI port. With HDMI, the display just flicks on and off again repeatedly. The NEC 4K does not support MST as best I can see, so I would be happy to try and run it at 30Hz (SST mode), but the options to change the refresh rates are missing from the Displays pref. I'm also happy to run my non-4K screen via HDMI, but as mentioned can't get HDMI to drive any of the external screens. Any advice would be gratefully received.Reply

This configuration also works well in clamshell mode, with just the 2 external displays connected.

The only issue I've observed so far is the output on the HDMI display is a bit choppy, especially when moving windows around the desktop rapidly. I am guessing this is due to the 30Hz refresh rate. It would be nice if I could drive both external displays at 60Hz, but I haven't found a way to do that yet.Reply

"Only a small group of monitors from ASUS and Sharp were supported for running at 3840x2160 with a 60Hz refresh rate..."

Not to put too fine a point on it, but that small group was essentially all she wrote when the OS shipped. As far as I know, there are only 6 currently available 4K, 60 Hz displays that cost less than $15K: the ASUS PQ321Q and PQ321QE, Dell UP2414Q and UP3214Q, and Sharp PN-K321 and PN-K322B. So basically Mavericks shipped without support for the Dell 4K displays (which were released a couple months after Mavericks) or DisplayID 1.3 (which was finalized less than 2 weeks before Mavericks was released).Reply

Ah, I see the Samsung U28D590D did finally start shipping a couple weeks ago. I'm pretty sure the Philips 288P6LJEB hasn't left the barn yet, though, and I hadn't even come across NEC's entry into the fray. Lenovo, LG and ViewSonic have all announced affordable 4K displays which aren't out yet, and Asus has the 28" PB287Q in the works as well.

Regardless, unless I missed something that was actually shipping when Mavericks was released, my point still stands.Reply

TN-panels are not interesting in this category which the low-end 4k monitors are. Dell's 24-inch (IPS/4K) is pretty poor too in some areas but at least performs a lot better than the 28-inch TN ones and is really good if calibrated properly, and has a lower price point than the 31.5-inch Sharp-panels. Usability in Windows isn't really a strong suite however and in OS X I guess most will use it with 1080 HiDPI which basically gets you the working space of a 1920x1080 monitor. So to really use these monitors you'd probably need the 31.5-inch with Sharp-panels any way. Those that has shipped has basically support on OS X now. Sharp, Asus, Dell.Reply

In fact I view the MST 4K displays as something of an early hacked stopgap solution. These MST 4K displays like the Sharp and ASUS (for example) will likely be superseded by revised SST models in due time.

Every model of 4K display that I have seen thus far makes some kind of compromise that can be unpalatable in some way depending on the user / use case.

So I wouldn't dismiss one specific group of them at this time for shortcoming unless I was prepared to dismiss them all.Reply

Well, technically, OG Thunderbolt provides more bandwidth than DP 1.2, and even the first generations can carry two DP 1.1a HBR1 streams, which is equivalent to what a DP 1.2 main link can manage and plenty for a single 4K display. The only problem is getting the two DP 1.1a streams out of a single Thunderbolt port and into your display with available hardware.

With the Asus, Sharp and Samsung(!) displays that can take 2x HDMI inputs for 60 Hz, you can use a pair of miniDP to High Speed HDMI active adapters if you have two available Thunderbolt ports, or a pair of Thunderbolt docks with High Speed HDMI ports in a daisy chain if you only have a single Thunderbolt port to spare. The Dell 4K displays can only be driven at 30 Hz or in Picture by Picture mode unless you have a Thunderbolt 2 / DP 1.2 source. Unfortunately, to date, Intel has only produced Thunderbolt controllers with a single DP source protocol adapter, so you need to use two controllers / devices to access both DP streams.

The DisplayPort MST spec actually has provisions for MST concentrators as well as hubs, and ST has produced chips which could enable the creation of devices that would allow you to take multiple DP 1.1a or HDMI signals, combine them, and output them via a single DP 1.2 port using MST. http://www.st.com/st-web-ui/static/active/en/resou... So someday we may see adapters that allow older PCs to drive these first gen tiled 4K displays which rely on DP 1.2 MST to achieve 60 Hz.Reply

Only in some markets these displays in Europe doesn't have two HDMI's that you can use to drive it at 60Hz (as two screens). So you can do this on say Asus PQ321Q but not PQ321QE. You better use DP1.2 MST in Europe. That's Sharp's fault on this particular model of course though. Samsung and Dell does the same and don't offer dual-hdmi either however.Reply

Seems more like it would be ASUS's fault, rather than Sharp's. I'm still confused as to why the Euro version only has one input though, especially considering it ends up costing more than the American version.

So yeah, the Samsung apparently only supports dual HDMI input in PBP mode. The vertical tearing should be better than on the Dell at least, where you're forced to use sources with different timing schemes. So perhaps OK if your drivers support Collage Mode / Eyefinity Display Groups / Surround with two 1920 x 2160 tiles.Reply

Nah, the same is true for the European Sharp PN-K321/H too. No HDMI. Asus is just a rebadged Sharp. Dell on their own version with the IGZO-panel they don't provide dual-HDMI either. DP1.2 MST it is for a long while as next gen graphics (like Maxwell) don't support stuff like HDMI 2.0/600MHz yet, so it wouldn't matter if the monitors or sets get support for HDMI 2.0 in silicon either. By the time support for that arrives at both ends you will probably have support for DP SST at 3840x2160 any way.Reply

Any clue if MST hubs work for multi display output? I heard it kind of...but not really worked in a 10.9.3 beta before, like it showed mirrored displays for someone, but no spanning (whereas they don't get recognized at all in 10.9.2 I think).Reply

I think there is a lot of Apple bias here. Apple is normally good at imaging but how can you claim:

"Apple's Hi-DPI scaling and seamless integration across the ecosystem continues to be awesome."

When in the article you describe that adjusting scaling requires rendering at non-native resolutions, involving both extra processing and imperfect rendering.

I am concluding that Windows dpi support is better (on Vista or later OSes), since it allows any dpi to be specified with correct scaling at native resolution (provided applications cooperate). Am I right?Reply

I'm sorry to disappoint you, but no.As an 110% Windows user I have admitted for like 5 years now that the DPI scaling in Windows is fundamentally wrong and broken. Even if Windows 'windows' upscale fine, many programs display a mess of text or icons across the screen. And even then, other programs stay in a 1:1 scale completely overriding what Windows says it to do. Other programs upscale text but not the window boxes, so you can't read the text fully and even missing some check boxes to be checked for instance, in settings.Have you read Jarred analysis ? http://www.anandtech.com/show/7838/dell-xps-15-has...

Windows in a monster screen/monitor in very high res looks absolutely fine. Try to use it in anything with 15" without proper scaling and then cry. Windows should be doing what Android/ios/WindowsPhone is doing with FHD or higher in smartphones or tablets: proper scaling.This is what Apple is bringing to the desktop, and the way they are doing it is nothing short of awesome.I've never bought an Apple product and I'm a Windows guy by choice and necessity, but Apple is doing it right in this regard. I hope Microsoft could 'start their photocopiers' and address this issue in Windows.Reply

But these applications are obviously malfunctioning. Maybe OSX has a mediocre performance for all apps, while Windows has perfect output for correctly written apps and terrible output for badly written apps? Is that it?Reply

Apps like the newly released SQLServer 2014 has obvious scaling problems in its GUI when running on rMBP (with large fonts). If such a signature product from Microsoft itself cannot be held to a higher standard, I think the hopes for other applications are gone. The OS itself must do this right, not depending on apps to implement hidpi correct, it doesn't work. Regardless if it's caused by sloppy programmers or not. Then again, if MS' SQLServer developers cannot get this right, why should the MS' Windows developers?Reply

Internally OS X supports the same sort of infinite resolution independence as Windows does. When moving to desktop high-DPI, Apple made a pragmatic decision to step halfway. Rather than exposing broken true resolution independence, they exposed fully functional @2x. Picking this target allowed developers to take reasonable and achievable steps in their applications to support the higher DPI mode. Also it allowed a fully usable and predictable fallback solution for when the app was not re-designed.

They also went the extra mile which surprised me at the time, Apple isn't known for creating and exposing advanced options. When you draw the desktop at "Best for Retina" or native mode, the display drives at the actual pixel resolution (say 2880x1800). When you pick one of the "more space" modes it draws to the frame buffer at 2x the resolution selected (using the @2x assets), and then scales it back to the pixel resolution. This means the interpolated image is pretty darn sharp, and extremely usable if you do in fact need more space. You CAN tell the difference if you look carefully, but for normal use it is a great compromise. I am not sure if the larger text modes work the same way. Having switched to one now, it is kinda blurry so I think it is rendering at 2048x1536 and scaling up to 2880x1800.

So yes, from a philosophical place I guess you could say Windows' DPI scaling is better. However, I think that is pretty disingenuous. Apple's OS has support for true infinite resolution independence. They elected not to leverage it in the interest of having a real working functional solution in the near-term. Which we have. Using a retina-enabled device from Apple today is a really great experience. Most applications are native and crisp.Reply

Forgot to mention, keep in mind you can still target views @1x. Preview, Quicktime Player, and Final Cut Pro X all demonstrate the ability to render content at pixel resolution inside of the @2x application. Anybody can do this if it is advantageous to their application design to have that native pixel content floating around. So it truly is resolution independent inside of the @2x restriction too.Reply

I am wondering whether Anandtech will post a more detail review of OS X 10.9.3 performance using the 4K display with all these different resolution and scaling on different hardares. My personally experience on my Macbook Pro 15 inch Late 2013 with nVidia 750m is pretty positive but I just want to see some benchmark compare Mac Pro (AMD), High End Macbook Pro (nVidia) and Low End Macbook Pro (Intel).Reply

Why doesnt the 2012 15" Retina Macbook Pro's get 60hz 4K support as well? they have a almost identical dedicated GPU (Nvidia 650M). And every 2012 15"r has dedicated graphics, unlike the 2013 models.Reply

Yes, it seems that 10.9.3 breaks things for some multi-monitor setups. For some folks, downloading and installing the combo update and/or resetting PRAM fixed the issue. For others, rolling back to 10.9.2 was required.Reply

Sorry, this may have been answered in the comments, but I'm seeing a bit of conflicting information. I have a 13" MBPr Late 2013. If I get the Dell UP2414Q, can I drive 4K@60 with the DP? The article and some comments make me think no, but the Apple Support article (http://support.apple.com/kb/HT6008) doesn't differentiate between 15" & 13" and seems to allude that it is possible by changing the display settings.Also, if it is possible, can I still use the internal display at the same time I'm using the Dell running 4K60?ThanksReply

Unfortunately the 10.9.3 release notes themselves are the accurate ones. Late 2013 15" MBPs only at this point. It'd be great to see that support widened to the 13"- but Apple may not be satisfied with the 4k/60hz performance of the non-Pro Iris that doesn't have the eDRAM for extra bandwidth like the 15"...Reply

So perhaps a big ooops here. I've just ordered the UP2414Q, going by the clear (and official) documentation referenced above that both MBP late 2013 will drive it at 60hz. How could Apple have made such a mistake in this document--if indeed it is a mistake. Language quoted here: "MacBook Pro (Retina, Late 2013) or Mac Pro (Late 2013) also support 60 Hz displays using multi-stream transport (MST). These displays need to be manually configured to use MST. Follow the steps below to use the display's built-in controls to enable this feature."Reply

Can the 15'' MBP with the discreet graphics only run 1 4k External Display at 60Hz? I know it can run 2 4k display's + its own display but I haven't got a chance to try it at 60Hz. My display maxed out at 50Hz so I returned them - I'm now wondering if I should pull the trigger on dual new 4k Sammy's?Reply

Highly unlikely. 4K displays count as two displays, and the NVIDIA dGPU only supports 4 display outputs. If it were possible, it would have to blank the built-in panel, and it would require the driver to be capable of creating multiple display groups. Can any NVIDIA GeForce cards even drive dual 4K displays at 60 Hz under Windows with stock drivers?Reply

I have verified MBP with nVidia 750m can only run 1 4k External display at 60Hz. After I hooked up my Dell UP2414Q on one of my thunderbot port, I can't even push my 1080p monitor on the second thunderbot port. Fortunately, my internal monitor + hdmi port still functional. So I can have 3 display devices running simultaneously. Reply

As a happy owner of a late 2013 MBP and a Dell UP2414Q - you can drive the display at 3840x2160@60Hz too, all you have to do is press and hold the Alt key when clicking on the "Scaled" radio button in the display settings dialog. You get a long list of resolutions you can pick from.Reply

I guess it's good someone (anandtech) is taking on the role of early adopter for 4K, but really I just want to skip right over 4K and focus on making 8K the new industry standard. Why half ass it?Reply

4K @ 60Hz works on the latest 13" rMBP's under bootcamp using Intel Collage mode so it is possible under OS X but unlikely that Apple will implement given their history of purposely limiting features to set greater divides between product models.

I just called Apple support and they informed me flat out that the MacPro does not tile 4K and drives it as a single 3840-by-2160 at 60Hz. This seems to me to be completely contradictory to everything else I've read which states that there is no single tiling option available now. Who's right?Reply

There are still problems with the driver for 4K on 60H with the Sharp. The starupscreen is still stretched. Connecting with displayport and then connection another display with HDMI only works when the 2nd display is used. When off you get weird screens. I am surprised the tests here did not reveal this.Reply

Can the updated 13" MP Retina (ie, the "early 2015" model) drive 4K@60Hz? According to the official Apple document (https://support.apple.com/en-us/HT202856), it does look like the answer is 'yes', but perhaps someone can confirm (and perhaps update this article). Reply